Production of hydrogen and carbon black by methane decomposition using DC-RF hybrid thermal plasmas

Abstract

Abstract-A continuous production of carbon black and hydrogen has been investigated by thermal decomposition of methane using a prototype processing system of direct current (dc)-radio frequency (RF) hybrid thermal plasma, which has great advantage over other thermal sources like combustion or dc plasma torches in synthesizing new nanostructured materials by providing high-temperature environment and longer residence time for reactant gases due to its larger hot core region, and lower flow velocity. Appropriate operation conditions and reactor geometries for the effective synthesis process are predicted first from the relevant theoretical bases, such as thermodynamic equilibrium calculations, two-dimensional thermal flow analysis, and chemical kinetic simulation. Based on these derived operation and design parameters, a reaction chamber and a dc-RF hybrid torch are fabricated for the processing system, which is followed by methane decomposition experiments with it. The methane injected into the processing system is converted mostly into hydrogen with a small volume fraction of acetylene, and fine carbon particles of 20-50 nm are identified from their transmission electron microscope images. Material analyses of Brunauer-Emmett-Teller , dibutyl phthalate adsorption, and X-ray diffraction indicate that the synthesized carbon black has excellent properties, such as large surface area, high electrical conductivity, and highly graphitized structures with good crystallization.

NEREU Project: Construction of a Plasma Reactor for Reform of Greenhouse Gases for Treatment of Wastewater of the Marine Farms

“…Therefore, it is necessary to make use of other processes capable of breaking the forces of atraction between molecules [12,14,15].…”

“…Due to incomplete combustion in the presence of oxygen, the process is inevitably accompanied by the emission of CO, CO 2 , SO 2 , NO x , and volatile hydrocarbons. In addition, the maximum reaction temperature achievable is from 1500 to 2000 K [11][12][13][14][15].…”

Thermal Plasma Synthesis of Nano-Sized Powders

“…5 at very high growth rate. Besides CNTs, the high enthalpy of thermal plasma has also been employed as a main heat source to decompose hydrocarbons into hydrogen rich fuels and solid carbon black, so called, plasma black [65][66][67][68][69][70]. As reported in many other papers and patents [65][66][67][68][69][70], plasma black can be formed like crinkled papers having well-developed graphite crystallites since they are produced at high temperatures over 2,000 K by thermal plasmas.…”

Produção de Hidrogênio e Negro de Carbono a partir da Degradação de Metano por Plasma Térmico

“…Entre a variedade de métodos, a tecnologia de plasma térmico tornou-se popular industrialmente, devido à sua elevada eficiência e por ser considerado um processo ambientalmente limpo (KIM et al, 2005), (GUO; KIM, 2008).…”

“…Devido à combustão incompleta na presença de oxigênio, o processo é inevitavelmente acompanhado pela emissão de CO, CO 2 , SO 2 , NO x e hidrocarbonetos voláteis (KIM et al, 2005;FABRY;FLAMANT;FULCHERI, 2001). Além disso, a temperatura máxima de reação alcançável é de 1500 K a 2000 K (KIM et al, 2005).…”